Widely deployable charging system for vehicles.

ABSTRACT

A mechanical, electrical and telecommunication system to electrically connect a vehicle to an electricity source to transfer energy to the vehicle is presented. The system is designed to tolerate misalignments of a parked vehicle with respect to the parking stall. An important component of the system is a pair of rigid, insulating strips with a series of conductors on each of them, placed at approximately right angles to each other. One of the strips is mounted on the infrastructure or road side and the other on the vehicle. The two strips cover the lateral and longitudinal misalignment of the parked vehicle. As long as the two strips have a cross point; the connection can be made by the conductors in the overlap region. The system is designed to operate only in the active presence and active desire of a vehicle to connect to the infrastructure or road side stationary part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority over U.S. Provisional PatentApplication 60/947,954, filed Jul. 4, 2007, titled “Widely deployablecharging system for vehicles”, which is incorporated herein by referencein its entirety.

DESCRIPTION OF DRAWINGS

FIG. 1: L and S connectors.

FIG. 2: Electrical connections and geometry definition.

FIG. 3: Splitting the L-connector conductors.

FIG. 4: Front underside mounting.

FIG. 5: Underside mounting.

FIG. 6: Actuating Mechanism.

FIG. 7: Mechanical system: Configuration 1.

FIG. 8: Mechanical system: Configuration 2.

FIG. 9: Equal force distributor replacement mechanism for link 10.

FIG. 10: Alignment preserving replacement mechanism for link 10

FIG. 11: Electrical connections, interlock and geometry definition

FIG. 12: Steps to select contacting conductors, executing onmicroprocessor A.

FIG. 13 Steps to select contacting conductors, executing onmicroprocessor A.

FIG. 14 Steps to select contacting conductors, executing onmicroprocessor A.

FIG. 15: Connection quality check.

FIG. 16: Using parking brake or similar lever for charging mechanismactuation.

FIG. 17: L and S connector (Grid style)

BACKGROUND AND PRIOR ART

After reviewing over 150 patents from the class 320.109, class 439.10and class 439.34, it is deemed that this invention is unique and newover the prior art.

The problem of transferring electrical energy to moving vehicles hasreceived substantial attention in the transportation and materialhandling community. Consequently there is a rich array of technologiesavailable in the prior art. The prior art can be broadly classified intofollowing categories:

Cable with connectors or pedals: (U.S. Pat. No. 6,185,501) All suchsystems involve manual connection and disconnection of vehicle to theinfrastructure. Apart from the fact that these systems do not offerautomation, they do have safety issues arising from a potentiallycomplex tangle of wires to be managed as well as possibilities ofaccidental drive off by a forgetful driver while the vehicle is stilltethered to charging outlet.

Large scale inductive transfer: (U.S. Pat. No. 5,573,090). These systemsinvolve oversized primary induction coils embedded under parking spot.Large dimensions are intended to cover the vehicle parkingmisalignments. Such systems suffer from the excessive inductive energywastage and involve complex infrastructure modifications that areunsuitable for modern personal use vehicles.

Overhead pantographs: (RE29994, U.S. Pat. No. 3,955,657, U.S. Pat. No.5,651,434) All such systems are bulky intrusive configurations that needinvolved installation and maintenance of overhead bus bars. Thesesystems also involve single energy transfer channel due to the crossbars with single conductors. The second connectivity channel is takenfrom underground connection. This leaves no room for additional channelsfor energy transfer interlocks, which are crucial from the operationalsafety viewpoint.

Electromagnetic radiation coupling: (U.S. Pat. No. 7,068,991, U.S. Pat.No. 6,792,259, U.S. Pat. No. 6,114,834, U.S. Pat. No. 5,982,139) Ahandful of patents refer to a narrow radiation beam emanating from aninfrastructure device and hitting energy receiving devices on the roofof vehicles. Such systems still need a fair amount of manual alignment,but most importantly have very limited energy transfer rates for a safelevel of radiation.

Conical/compliant receptacles: (U.S. Pat. No. 7,023,177, U.S. Pat. No.6,614,204, U.S. Pat. No. 5,850,135, U.S. Pat. No. 5,696,367, U.S. Pat.No. 5,498,948, U.S. Pat. No. 5,272,431) These systems offer a limitedtolerance to vehicle to parking stall misalignments. The operator isstill expected to home into the receiving or compliant zone of thereceptacle and stop just in time not to push against the infrastructure.In addition to expecting specific behavior from drivers, an accidentalpoor alignments as well as fast approach pose collision threat and willdegraded the operation and reliability of such systems.

Active location seeking robotic arms/trolleys: (U.S. Pat. No. 6,859,010,U.S. Pat. No. 5,821,731, U.S. Pat. No. 5,703,461, U.S. Pat. No.5,696,367, U.S. Pat. No. 5,654,621, U.S. Pat. No. 5,646,500, U.S. Pat.No. 5,617,003, U.S. Pat. No. 5,461,298, U.S. Pat. No. 5,272,431) Thereare many variants of these systems depending on the sensing scheme usedas well as actuation schemes used. Such systems are relatively complexand depend on reliability of several sensors and motion control loops. Amiss-calibrated/drifted system could pose a spectrum of problems rangingfrom scratching the shiny paint of vehicle to simply not being able toconnect the vehicle. Apart from the intrusive nature of the roboticarms, both the trolleys as well as robotic systems are susceptible tovandalism in open infrastructure applications.

Physical and virtual guiding systems for homing: (U.S. Pat. No.6,525,510, U.S. Pat. No. 5,850,135, U.S. Pat. No. 5,461,298, U.S. Pat.No. 5,341,083, U.S. Pat. No. 4,496,896) The first category of thesesystems either employ mechanical guides for vehicle tires, forcing thevehicle to a relatively precise location for the automatic connector tomate with now precisely located vehicle side counterpart. Some othersystems involve passive guidance to the drives, either based on a sensorpair, a dashboard or infrastructure based display device or through gridmarkings on the pavement. Such systems are either large footprint andtend to be bulky, or are imprecise (passive guidance) and need furtherconnectivity assistance from conical, compliant or active searchcomponents.

Contactor arrays: Such systems have multiple connectors placed oninfrastructure that will end up connecting with relatively fewcontactors on the vehicle side and vice versa. The vehicle to parkingstall misalignment is compensated by multiple conductors. This patentgenerally falls in this category of devices. Specifically:

U.S. Pat. No. 6,307,347 describes a pair of two dimensional grids, eachgrid being permanently dedicated for one channel of connectivity. Thisnot only increases the number of connectors (proportional to l²) perchannel of connectivity, but also needs each grid big enough to toleratethe vehicle misalignment specs. Thus making the total # of contactors ton×l², where n is # of connectivity channels and l is the grid's lineardimension, which has to be bigger than vehicle parking tolerance in onedimension.

U.S. Pat. No. 5,651,434 has two overhead cables and the vehicle has apantograph with two contactors insulated from each other. Due to the oneto one correspondence between the infrastructure side and vehicle sidecontactors, this arrangement necessitates the two cables as well as thetwo pantograph connectors be separated laterally by the worst caselateral misalignment specs of the vehicle plus the lateral dimension ofthe pantograph contactors, making it a bulky system, which is difficultto extend beyond two connectivity channels, a prime safety requirementfrom ground fault detection viewpoint.

U.S. Pat. No. 5,523,666 has features similar to contactor arraystructures; however it still depends on the mating pair of contactors tobe brought together by active positioning. Again the one to onecorrespondence between the infrastructure and vehicle side connectorsmeans relatively precise alignment at least in one direction, betweenthe corresponding connectors is required. This alignment in the U.S.Pat. No. 5,523,666 is made by active positioning of the infrastructurerails and suffers from the consequent disadvantages of an activepositioning system.

U.S. Pat. No. 5,252,078 is very similar to U.S. Pat. No. 5,523,666,except the relatively positioning of the mating connectors is achievedby passive compliant members. Both U.S. Pat. No. 5,252,078 and U.S. Pat.No. 5,523,666 suffer from the disadvantages of a system requiringprecise alignment—whether passive or active, as well as carry potentialfor damage and reduced reliability and safety due to driversaccidentally driving into the system.

U.S. Pat. No. 4,158,802 is an overhead contactor system with one to onecontactor correspondence between vehicle and infrastructure.Consequently suffers from either precise positioning or too largecontactor spacing and size. As described, this system is also bulky andneeds involved installation.

U.S. Pat. No. 4,850,879 is a front bumper variation of U.S. Pat. No.6,307,347. Both, U.S. Pat. No. 4,850,879 as well as U.S. Pat. No.6,307,347 describe conductor arrays that have contiguous domains ofconductors that are electrically connected to each other and representone single large conductor.

Corresponding to one conductor (or a group of conductors that areelectrically connected to each other) on ground, there is one and onlyone conductor on the vehicle that the ground conductor is permitted topair with. All inventions based on one to one conductor pairingnecessitate large individual conductors (or group of conductors) oraccurate positioning. In case of U.S. Pat. No. 4,850,879, former istrue. Additionally, U.S. Pat. No. 4,850,879 can be damaged due toaccidental driving in.

DETAILED DESCRIPTION OF THE INVENTION

A mechanical, electrical and telecommunication arrangement to transferelectrical energy to a vehicle is described in this invention. At thecore of the system (see FIG. 1) is a pair of linear arrays of conductiveelements insulated from each other. A specific rendition where one ofthe arrays is a 1×7 array (labeled as S-Connector) and the other is a2×1 labeled L connector is shown in the FIG. 1. One of the connectors(either S or L connector) is placed on the infrastructure side and theother on a vehicle. When the array on the vehicle is in the proximity ofthe array on the ground, such that the two have an overlap, one or bothof the arrays are moved towards each other. This causes the arrayelements—labeled as “conductors”, to mate and form an electrical contactin the overlap region. Depending on the relative position of the vehiclein the parking stall, an arbitrary group of conductors from S connectormay come in contact with an equally arbitrary group of conductors fromL-connector. A series of switches connected to each of the contactors,in cooperation with a microprocessor select the contactors in theoverlap region for use in the energy transfer process. Notice that thelengths of the array and their relative orientation to each other allowsfor a tolerance in the accuracy of parking a vehicle. In fact the lengthof each of the S and L connectors is the amount of allowable parkingtolerance in lateral and longitudinal direction, and is a direct designvariable to cover the parking inaccuracies in the respective directions.The following paragraph describes further design procedure to ensurereliable contact between the elements of two arrays upon contacting eachother. In the description, it is assumed that the intention is toestablish two electrical conductive paths between array “S connector”and array “L connector”. These will be referred to as + and − paths. Inthis example shown in FIG. 1, one of the conductors on the “L conductor”has polarity − and the other has polarity + in terms it electricalpotential.

In order to ensure a guaranteed contact of correct polarity, thegeometry of the conductors on the S and L connectors has to followcertain geometric constraints. Assuming the conductor dimensions are asshown in FIG. 2, the constraints are:

S_(C) + S_(G) < L_(C) Ensures that a L conductor contacts at least one Sconductor fully. S_(C) < L_(G) Ensures that S conductor does not shortneighboring L conductors. S_(C) + 2S_(G) > L_(C) Ensures that Lconductor does not short 3 neighboring S conductors. 2S_(C) + 2S_(G) =Ensures that + and − connections end up with same L_(C) + L_(G)geometry. Note that one solution to these constraints is: S_(G) = S_(C),L_(C) = (3 − x) S_(C), L_(G) = (1 + x) S_(C), where x is number between0 and 1.

Once the connectors are brought to mate with each other, amicroprocessor reads the potential on each of the S-connector conductors(see FIG. 2). Using these measurements, the microprocessor can figureout the specific conductors on the S-connector that have mated withconductors on L connector as well as their polarity. In turn themicroprocessor switches on the appropriate MSOFETs from the Switch Bank,to ensure correct electrical polarity to appear at the Load+ and Load−terminals in FIG. 2.

As a further safety modification, the conductors on the L-connector canbe divided into smaller pieces as shown in FIG. 3. Once the contact ismade, a switching bank (not shown) similar to the one shown in FIG. 2,is used to power up only the mating L-connector conductors. This ensuresthat unused and possibly exposed L-connector conductors carry noelectrical potential. This improves safety and eliminates accidentalshort circuits.

It should be noted that the voltages used across the mating connectorscan be any low voltages such as 12 or 24V. Electronic pre and postprocessing will be used to down and up convert the low interfacevoltages to any desired input/output voltages. This is to furtherenhance safety and reduce operational hazard.

There are several locations on the vehicle for mounting the movableconnector (either S or L). FIG. 4 and FIG. 5 show two such examples.Both of these examples show the infrastructure side connector mounted onthe pavement. One can think of many alternate locations and mechanismswith or without pavement mount.

Among other alternatives is a configuration with roadside connectormounted on an actuator and vehicle side connector being mounted rigidlyon the vehicle.

The motion involved to mate the connectors, is a simple one dimensionalmotion and can be accomplished by many different mechanicalarrangements. FIG. 6 shows an actuating mechanism to mate the twoconnectors. Specifically, the motor 1—mounted on vehicle actuates a feedscrew 2. The other end of the feed screw is mounted on bearings 12,which is also attached to the vehicle. This bearing can sense thevertical bearing force. The link 8 is connected to the feed screw 2 by afeed nut 3. The link 8 further connects up with link 10 with a pin. Oneend of link 10 is pivoted on link 5 and the other end carries a solidrubber tire 11 and one of the connectors—either S or L. The link 5 ispivoted to vehicle using member 7. The tension spring 9 is anchored tovehicle at one end exerts an upward pull on the member 10 by being intension at the position shown. The compression spring 6 normally pushesmember 5 against the stop 4. The stop 4 is attached to the vehicle. Themechanism stays in its retracted position 15 when the vehicle is inmotion. After the vehicle is parked and ready for charge, amicroprocessor runs the motor 1 and first brings the mechanism in toposition 16 in which the connector 13 (S or L) just touches theconnector 14 (L or S). During this motion, the link 5 continues to bepushed by spring 6 against stop 4. The motor 1 then moves further andthe connector 13 moves from position 16 to 17. During this motion, thelink 5 moves against the spring 6. The motor continues to push till acertain force is measured at the bearings 12. The bearing force sensoris optional. Same information can be sensed by monitoring the motorcurrent. The last part of the motion from position 16 to 17 causes theconductors to slide against each other with a sizable interface force,thus ensuring a good quality contact by cleaning the debris and anyoxide film that may have formed.

In the case when the mechanism in FIG. 6 is in its extended position(i.e. connector 13 in position 17), and a passenger enters the vehicle,thus compressing the vehicle suspension springs by a few inches. Suchmotion will be well tolerated by the mechanism in FIG. 6 by furthercompressing the spring 6. The allowable stroke of the spring 6 should bedesigned appropriately to accommodate the vehicle suspension compliance.

The mechanism is able to operate with a wide range of initial separationbetween connector 13 and 14. The link 10 will extend till it encountersthe reaction from the conductor 14. At that point—independent of theangular deployment of link 10, the conductors will start sliding againstspring 6.

The overall mechanical system can be configured in many ways. Twoexamples are shown in FIG. 7 and FIG. 8. The Configuration #1 (FIG. 7)uses only one motor for actuation and exerts almost equal forces on thetwo (right and left) copies of the link 10. The Configuration #2 (FIG.8) uses two independent copies of the actuating mechanism. After theconnectors 13 and 14 have made their initial contact, the location(along the connector 13) of the contact point will be sensed through acapacitive proximity sensor (not shown) and appropriate forces areapplied to the two copies of the link 10, such that the moments of theseforces are balanced about the contact point. The force computationsbeing done by the microprocessor after the contact point sensing.Alternatively the two forces will be applied such that the connector 13swings through some small positive and negative angle, while monitoringthe quality of the connection using a small dummy potential applied tothe connector 14. Once a good quality connection is sensed, the forceproportion on the two actuators will be frozen for subsequent motion.

FIG. 7 and FIG. 8 also show energized coils (or permanent magnets) C1,C2 and magnetometers H. The magnetic field emanating from energizedcoils (or magnets) C1 and C2 will be sensed by magnetometer H. Thesensed magnetic field will be converted to relative position betweenconnector 14 and 13. This information will be provided to user via auser interface. This information will be used as an optional feedback tothe user during parking. Depending on the specific design, the magneticfield from C1 and C2, as sensed by the magnetometers H, will bedistinguished by polarity or timing.

Fail safe features: In the normal circumstances, an electronicinterlocking with the ignition key of the vehicle will be employed toensure that the mechanism is fully retracted before the vehicle startsto move. However, in case of malfunction, there are two level fail safefeatures incorporated in the mechanism. The first feature is the softrubber wheel 11, which will smoothly rotate upon touching the road, thuscausing no harm to the drivability of the vehicle. In case the mechanismis stuck in a position such that a large portion of road forces arebeing borne by the rubber tire 11, the second feature kicks in. Thebreakable link 8 will break up under the road forces that aretransmitted to it via wheel 11 and link 10. Once broken, the spring 9will pull the linkage 10 up to its retracted position or close to it.Alternatively, the pin connecting the link 8 and lead nut 3 can be abreakable link to achieve a similar fault protection.

In an alternative mechanism, the motor 1, the feed screw 2 and the feednut 3 will be eliminated. The link 8 will be replaced by mechanisms suchas shown in FIG. 9 and FIG. 10. The mechanism in FIG. 9 is an equalforce distribution mechanism in which the two copies of the link 10 willbe pushed down with almost equal force. The mechanism in FIG. 10 is analignment preserving mechanism in which the connector 13 will be keptparallel to its original position.

In an alternative mechanism, the motor 1, the feed screw 2 and feed nut3 will be replaced by a pneumatic cylinder. Further the air supply canbe centrally or locally heated. The heated air will be intentionallyleaked out of the pneumatic cylinder periodically to melt away anyaccumulated snow or frozen moisture in cold weather. The periodic hotair bursts will also help clear away any normal debris that may haveaccumulated on the actuating mechanism. As an additional cold weatherprotection, optional heating elements can be embedded in the conductingarrays to ensure all surface moisture is melted away.

Once the mechanical motion is completed, the contactor selection processbegins. One example of such algorithm is presented in FIG. 12, FIG. 13and FIG. 14. This is followed by a connection quality check described inFIG. 15. Finally a communication with the utility grid is established tooptimize charging process parameters, such as rate and time of chargingto realize cheapest energy costs or any other goal set by the user.Specific details of such transaction are not intended to be part of thisinvention.

Some of the additional features for reliability improvement are:

1. A set of wipers on the leading edge of the connector 13, arrangedsuch that they end up wiping the relevant portion of the connector 14 asthe two connectors approach during mating.

2. A dust cover to cover the retracted position of the connector 13 andits moving linkage.

3. A circuit design to ensure that the exposed conductors of connector13 and 14 are kept at a negative potential, so that they get protectedfrom degrading by the cathodic protection.

4. A circuit design to ensure that the vehicle tires are kept at anegative potential, so that they get protected from degrading by thecathodic protection.

Unique Features of the Invention and their Market Value

1. No need for precise vehicle positioning. Normal parking accuracyusing the usual painted parking stall markings will be sufficient tomake a successful contact.

2. Static and movable parts of the connector are configurable. In oneconfiguration, static connector is on the infrastructure side, enablingwide scale deployment. In other configuration, the static connector ison the vehicle, minimizing changes required on the vehicle.

3. No tangle of wires or mechanical arms emanating to/from a group ofvehicles being charged.

4. Self cleaning of the contact surfaces by sliding motion across eachother before the electrical potential is established. This ensures highquality of contact.

5. Elimination of sparking by a microprocessor that switches on theelectrical potential only after ensuring that a quality connection hasbeen established.

6. Low voltage across interfacing conductors ensuring human safety.

7. Only relevant conductors are turned on after ensuring a good contactusing a small dummy voltage to test the connection quality. This keepsthe conductors normally de-energized to further reduce human hazard.

8. Individually switched multiple conductors enable pinpointedenergizing of relevant conductors for safe operation and shutdown duringdetected short circuits from accidental nails or other metal debrislanding on the conductor. The energized section of the connector willalways be first swept for debris and then covered by the matingconnector.

1. An apparatus which electrically connects a first group of electricterminals on a first object to a second group of electric terminals on asecond object comprising: a first array of one or more conductiveelements, each electrically connected to one of the members of the firstgroup of electric terminals; a second array of one or more conductiveelements, each connected by a first group of electrical switches to eachmember of the second group of electric terminals; and an actuatingmechanism which is attached to the first array of conductive elementsand contacts the first array of conductive elements with the secondarray of conductive elements or is attached to the second array ofconductive elements and contacts the second array of conductive elementswith the first array of conductive elements.
 2. The apparatus of claim29, further comprising of a microprocessor connected to each of theelectrical switches from the first set of electrical switches that areconnected to second array, which can determine the potential of theconductive elements of the second array and activate the first set ofelectrical switches.
 3. The apparatus of claim 2 with actuatingmechanism with at least one breakable member and a biasing force toinitiate retraction and keep the mechanism retracted under a faultcondition in a way that will pose no hazard to the surrounding.
 4. Theapparatus of claim 3 where the biasing force is provided by a spring. 5.The apparatus of claim 3 where the biasing force is provided by gravity.6. The apparatus of claim 3 where the breakable member can be restoredto its unbroken state.
 7. The apparatus of claim 6 where the breakablemember can be broken and restored under an electrical control.